Samuel Johnson Prize won by biography of 'repellent' poet
Author Lucy Hughes-Hallett has won the Samuel Johnson Prize for Non-Fiction for her biography of philandering Italian poet and politician Gabriele D'Annunzio.
The Pike "transcends the conventions of biography", the judges said.
Hughes-Hallett was announced as the winner in a ceremony at the Royal Institute of British Architects in London on Monday night.
The prize, now in its 15th year, is worth £20,000.
Hughes-Hallett's book beat Charles Moore's Margaret Thatcher: The Authorized Biography, Volume One: Not for Turning and Dave Goulson's A Sting In The Tale, about the mysterious ways of the bumblebee.
Also on the shortlist were Empires of the Dead by David Crane; Return of a King by William Dalrymple and Under Another Sky by Charlotte Higgins.
The Pike, published by 4th Estate, tells the life story of D'Annunzio, an Italian artist and womaniser who became a national hero and radical right-wing revolutionary.
"Readers of The Pike will surely admire Lucy Hughes-Hallett's writing, and her intricate crafting of the narrative," said Martin Rees, Astronomer Royal and chair of judges.
"Her original experimentation with form transcends the conventions of biography.
"And they will be transfixed by her vivid portrayal of D'Annunzio - how this repellent egotist quickly gained literary celebrity - and how, thereafter, his incendiary oratory, and foolhardy bravery influenced Italy's involvement in World War One and the subsequent rise of Mussolini.
"The book shows how fascism rose partly as a perversion of nationalism - a trend still sadly relevant in today's world."
Rees's fellow judges were historians Mary Beard and Peter Hennessy; director of Liberty Shami Chakrabarti; and writer and reviewer James McConnachie.
'Flowers and poetry and sex'
In a recent interview with BBC Radio 4's World at One, Hughes-Hallett said that what interested her about D'Annunzio was that he was "incredibly quick on picking up on an innovative literary form or a new hairstyle or - more importantly - a new political philosophy".
"Writing about him meant that I was writing about the entire cultural ambience in which he lived," she said.
"He was a decadent and he was a great enjoyer the good things of life - flowers and poetry and sex, he was an enthusiastic and surprisingly successful seducer."
Hughes-Hallett's previous books are Cleopatra: Histories, Dreams and Distortions and Heroes: Saviours, Traitors and Supermen.
Jonathan Ruppin, web editor for Foyles bookshops, said: "As well as being a much-needed modern analysis of a dangerously charismatic figure, the book stands as an eloquent riposte to all those who talk of the death of serious biography.
"Hughes-Hallett ignores no aspect of his fulcral role in the rise of Italian fascism."
The Samuel Johnson Prize for Non-Fiction is open to books in the areas of current affairs, history, politics, science, sport, travel, biography, autobiography and the arts.
Last year's winner was Wade Davis's book Into the Silence: The Great War, Mallory and the Conquest of Everest, about explorer George Mallory's attempt to conquer Everest.